How can I design a transistor switch for a 10-Ohm load with a +5V supply?

In summary, the transistor needs a current to turn it on, and the book we are using does not provide enough information to help me find that current. I am currently trying to find an example in the book that I can use to find that current.
  • #1
YAHA
121
0

Homework Statement



I am given a problem for my electronics class that asks to design a transistor switch that will switch a 10-Ohm load powered from a +5V supply. The transistor beta is about 50.

It also asks which current is needed to turn the transistor fully on (saturate it so that the collector-emitter voltage is less than 0.3V)

Homework Equations






The Attempt at a Solution



My biggest problem is that the book we use SUCKS. I am simply lacking material and, maybe, some examples. I have tried approaching the instructor, but his explanations do not "speak" to me.

I know what the circuit looks like. I then proceed to substitute the transistor with a diode+current source model. After that, I am befuddled.

Any help and preferably hints are appreciated!
 
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  • #2
YAHA said:

Homework Statement



I am given a problem for my electronics class that asks to design a transistor switch that will switch a 10-Ohm load powered from a +5V supply. The transistor beta is about 50.

It also asks which current is needed to turn the transistor fully on (saturate it so that the collector-emitter voltage is less than 0.3V)

Homework Equations






The Attempt at a Solution



My biggest problem is that the book we use SUCKS. I am simply lacking material and, maybe, some examples. I have tried approaching the instructor, but his explanations do not "speak" to me.

I know what the circuit looks like. I then proceed to substitute the transistor with a diode+current source model. After that, I am befuddled.

Any help and preferably hints are appreciated!

Can you show us the circuit diagram that you would use? If you have about 5V across a 10 Ohm load, what will the collector current of the NPN transistor be?

Now get a more accurate number for Ic by including the Vce,sat number in the calculation of the collector current. What is it now?

How is Beta defined? Using the definition of Beta, what can you say about the base current required to support the Ic value that you calculated?
 
  • #3
I am not really sure how I could show you. Your hints were helpful though :) I was able to "see" it. This has been a bizarre class. I can do QM and Solid State of diodes and transistors alright. However, when it comes to their applications, I am lost.
 

1. What is a transistor switch circuit?

A transistor switch circuit is a type of electronic circuit that uses transistors to control the flow of current, allowing it to be turned on or off like a switch. It can be used to control the operation of other electronic components or devices.

2. How does a transistor switch circuit work?

A transistor switch circuit works by using a small current or voltage to control a larger current or voltage. The transistor acts as a gate, either allowing or blocking the flow of electricity through the circuit. When the transistor is on, current can flow through the circuit, but when it is off, the current is blocked.

3. What are the advantages of using a transistor switch circuit?

There are several advantages to using a transistor switch circuit. They are smaller and more compact than traditional mechanical switches, making them ideal for use in electronic devices. They also have a faster response time and can handle higher currents and voltages. Additionally, transistors do not wear out like mechanical switches, making them more reliable and longer-lasting.

4. What are the different types of transistor switch circuits?

There are two main types of transistor switch circuits: NPN and PNP. NPN transistors use a negative voltage at the base to control the flow of current from the collector to the emitter, while PNP transistors use a positive voltage at the base. There are also different configurations of transistor switch circuits, such as common emitter, common collector, and common base.

5. What are some common applications of transistor switch circuits?

Transistor switch circuits are used in a wide range of electronic devices and applications. They can be found in computers, televisions, radios, and other consumer electronics. They are also commonly used in control systems, such as in automation and robotics, and in power supplies and amplifiers. Additionally, transistor switch circuits can be used in digital logic circuits to perform logical operations and control the flow of data.

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